Ontario’s police watchdog has opened its first investigation into a death that involved the police administration of the opioid overdose-reversal drug naloxone.

The Special Investigations Unit announced it was launching an investigation into the death of a 36-year-old Brampton, Ont., man.

The SIU said Peel region officers responded to a medical call early Monday, performing CPR and administering naloxone to the man.

The agency — which investigates reports involving police where there has been death or serious injury — says the man was pronounced dead at the scene.

The Ministry of Health announced in December 2017 that naloxone kits would be offered to all police forces in the province.

In a January letter addressed to the SIU, Ontario Association of Chiefs of Police President Bryan Larkin wrote that police forces should not have to inform the SIU of deaths or serious injuries if officers’ only interaction with the person was to administer the opioid-blocking drug.

He expressed concern that the threat of a lengthy inquiry could discourage officers from administering naloxone. His association asked the SIU to stop investigating cases of serious injury or death involving officers administering naloxone.

That request was rejected by the SIU in February. In a letter responding to Larkin, SIU Director Tony Loparco said the idea that an investigation would deter police action was akin to suggesting a police officer would choose not to get involved in a hostage situation because their actions might be scrutinized by the watchdog.

The SIU “fully expects chiefs of police to abide by their legal obligations and immediately notify this office of these types of incidents,” Loparco wrote.

He said while not every naloxone case would necessitate a full investigation, the SIU should be notified of each one in order to decide internally which cases to look into.

An SIU spokesperson confirmed that this case is the first time the unit has invoked its mandate on a death involving police administration of naloxone, but wouldn’t specify if it had received reports about other cases involving naloxone where investigations weren’t launched.

The organization has previously stated it does not track how many reports it has received regarding naloxone-related cases.